Fastener driving apparatus



United States Patent 3,115,941 FASTENER DRlVlNG APPARATUS fiscal" A. Wendel, Mundelein, ll assignor to Fastener Cor oration, Chicago, ill, a corporation of lllinois Filed May 22, 1961, Ser. No. 111,539 11 Claims. (Cl. 173-2) This invention relates to a fastener driving apparatus and, more particularly, to an apparatus having new and improved operating and control means.

Pneumatically operated tackers or staplers commonly employ a fluid pressure or compressed air operated piston for actuating a staple driver to sever a staple or other fastening device from a strip of interconnected staples and to drive the separated staple into a workpiece. The compressed air is selectively supplied to a cylinder in which the piston is mounted under the control of a control valve assembly. In order to reduce the force required to actuate the control valve, the fastener driving apparatus may include an air-operated control valve and a trip or pilot valve for controlling the application of compressed air for actuating the control valve.

Pneumatically operated tackers or staplers possess the capab' ity of high speed and relatively effortless operation which adapts them for use in applications where a large number of fastener driving operations must be performed in a relatively short period of time. However, existing devices of this type are generally operated by manual actuation of a trigger type control assembly which does not fully realize the advantages of speed and ease of operation. Prior devices have been proposed to avoid manual actuation of the trigger. As an example, Patent No. 2,756,426 discloses a stapler that is operated by placing the tool in engagement with the workpiece, and Patent No. 2,915,754 illustrates a stapler that is automatically operated at time spaced intervals by producing relative movement between the sta ler and the workpiece.

However, these prior devices have not been entirely satisfactory. In order to perform effectively, it is desirable to utilize a trip or pilot valve to reduce the forces required to operate the main control valve and to be able to operate the trip valve with a very small force. Moreover, it is desirable that the trip actuating pin of the strip valve have sufhcient travel to prevent reoperation of the stapling device due to the recoil travel of the device after the performance of a stapling operation. Further, it is desirable to provide for adjustment of the trip pin for variations in the dimensions of the stapling device and the valve operating linkages. It is also desirable to permit the operator of the tool to select or adjust the position of the stapler relative to the workpiece at which the trip valve operates the gun. For example, drivin." staples into some materials .would require an early nring point or operation with the tool spaced from the workpiece, whereas in other materials, the operator may elect to delay operation of the stapler until the nose of the driving device is touching the work.

Accordingly, o-..e object of the present invention is to provide a new and improved fastener driving appanatus.

Another object of the present invention is to provide a new and improved fastener driviw apparatus which overc the aforementioned ditficulties.

Another object of the present invention is to provide a fastener driving apparatus having new and improved control valve actuating means.

A further object of the present invention is to provide a new and improved trip valve for a fastener driving apparatus which requires but a small force to actuate it and which is not alfected by the recoil travel of the driving apparatus so as to minimize accidental reoperation of the driving apparatus.

Another object of the present invention is to provide such an apparatus including new and improved means for adjusting the trip valve.

Yet another object of the present invention is to provide a new and improved operating assembly for a fastener driving tool that is actua ed when the tool is brought into engagement with the work.

A further object of the present invention is to provide an operatin assembly wherein the actuating means for a trip valve is biased into its reset position by the pneumatic loading of the valve alone, thereby reducing the force required to actuate the trip valve.

in accordance with the present invention, there is provided an improved trip valve construction for controlling a fastener driving apparatus or" the type including a pneumatically operated fastener driving means controlled by a main control valve that is actuated by the trip valve. The trip valve construction includes a housing which forms a valve cylinder. A valve sleeve is positioned in the housing, and a trio valve element is slidably received in the sleeve. The fastener driving apparatus is provided with a trigger for moving the trip va ve element between a normal released position and an operated position. When the trip valve element is in the released position, compressed air flows through a first passageway in the housing into the valve chamber and then through passageways in the trip valve element and in the sleeve into the control valve. A second passageway in the housing and the valve sleeve connect the control valve to the atmosphere when the trip valve element is depressed or operated.

According to another feature of the present invention, the valve sleeve is carried within the valve housing in an adjusting cylinder. This cylinder can be moved into and out of the housing to move the sleeve and valve element relative to the valve housing. The adjustability of the cylinder permits the released position of the valve element relative to the housing to be changed.

According to another aspect of 16 present invention, there is provided a trigger actuating mechanism that is operated by movement of the fastener driving apparatus toward a workpiece. This mechanism includes a rigid actuating bar pivotally mounted at one end to the fastener riving apparatus and provided with a work engaging portion at its other end adapted to engage the workpiece. A connecting m mber pivotally interconnects the actuating bar and a trigger on the fastener driving apparatus that engages the trip valve element. Since the adjusting cylinder permits the trip valve element to be disposed at dillerent positions relative to the housing of the tool on which the trigger actuating mechanism is mounted, the position of the tool relative to the workpiece at the time that the main control valve is operated can be changed. ther objects and advantages of the present invention will become apparent from a consideration of the following detailed description in conjunction with the accompanying drawings, wherein:

FIG. 1 is an elevational view of a fastener driving apparatus incorporating the features of the present invention;

FIG. 2 is an enlarged sectional view of a trip valve assembly included in the driving apparatus which is taken along line 22 of FIG. 1 and which illustrates the trip valve assembly in a normal position; and

FIG. 3 is an enlarged sectional view similar to H6. 2 showing the trip valve assembly in an operated position.

Referring now to the drawings, there is illustrated a pneumatically operated fastener driving device, illustrated generally as lll, having a main control valve 11 (FIGS. 2 and 3) which, in response to each actuation thereof, operates the driving device or stapler 10 so that a staple supplied from a magazine 12 is driven outwardly through a drive track formed in a nosepiece 13 into a workpiece 141. The stapler 1% may be identical to the construction shown in the copending application of Oscar A. Wandel, Serial No. 527,697, filed August 11, 1955, which application is assigned to the same assignce as the present invention. In neumatic taclrcrs of this type, compressed air continuously supplied to a reservoir, such as one defined within a hollow handle thereof, is selectively admitted to a cylinder in the staple driving portion of the tacker housing under the control of the main valve 11. A piston slidably mounted in the cylinder is driven downwardly by the admitted compressed air to actuate a driver blade. During this movement, the end of the driver blade engages a staple supplied to the drive track in the nosepiece 13 and drives the engaged staple downwardly through the drive track into the workpiece 14. The piston and driver blade remain in this displaced position until the control valve 11 is released to permit the piston and driver blade to be returned to their normal position by resilient or pneumatic means.

To provide for the actuation of the main control valve 11, this valve includes a piston 15' reciprocally mounted in a chamber or cylinder 15. An O-ring 17 on the piston 15 forms a pneumatic seal between the piston 15 and the cylinder 16. A fluid port or passageway 18 controls the admission and exhaust of pneumatic fluid into the cylinder 16. The admission of the fluid into the chamber 16 moves the piston 15 upwardly to close the main control valve 11 so that compressed air is no longer supplied to the cylinder in the staple driving device. When the pneumatic fluid is exhausted from the cylinder 16, the piston 15 is driven downwardly by the pneumatic fluid to open the control valve 11 and admit fluid into the cylinder of the stapler it According to the present invention and in order to reduce the force required to operate the main control valve 11, there is provided a trip or pilot control valve 19 which controls the admission and exhaust of fluid to the cylinder 116. As herein illustrated, the trip Valve 33 includes a housing 20 forming a valve chamber defined by a bore 21 and a counterbore 22. The upper end of the bore 21 is closed by the wall defining the lower end of the cylinder 16. An adjusting cylinder or member 23 is threaded within the counterbore 22 of the housing 20 and is provided with a bore 24 in which a cylindrical valve sleeve 26 is mounted. An O-ring 25 carried on the sleeve 26 engages the wall of the bore 21 to prevent a flow of compressed air around the upper end of the sleeve 26. An O-ring 27 carried on the member 23 provides a pneumatic seal between the adjusting cylinder 23 and the wall of the counterbore 22.

To control the flow of fluid into and out of the cylinder 16, a trip valve element 28 is reciprocally mounted within a bore 29 formed in the valve sleeve 26. The trip va.ve element 2%; contains an enlarged portion 39 slidably received in the bore 29 and engaging the surface of the valve sleeve 26 in substantially airtight relation therewith. In addition, the trip valve element 28 includes a trip or actuating pin portion 31 of smaller diameter than the portion 39 that extends outwardly from the housing 2% through an aperture or passageway 32 in the adjusting member 23. The passageway 32 is of a larger diameter than the trip pin portion 31 to provide an air passage therebetween. The different diameter portions and 31 of the trip valve element 28 are interconnected by a beveled portion 33. An O-ring 34 mounted wi hin a recess in the lower end of the sleeve 26 normally engages the beveled portion 33 to prevent communication between the interior of the sleeve 26 and the atmosphere.

To provide for the admission of pressure fluid or compressed air into the cylinder 16, the housing Ztl is provided with a fluid inlet or passageway 35 communicating with the compressed air source and extending into the bore 21 above the upper surface of the valve sleeve 26. Additionally, the trip valve element 28 is provided '4 with a central passageway or opening 36 which is closed at its lower outer end and which communicates with a plurality of radially extending passageways 37 in the large diameter portion iii). In the released or normal condition of the valve 19, the passageways 37 are longitudinally aligned with a plurality of passageways 38 m the sleeve 26 which connect the interior of the valve sleeve 26 with the cylinder 16 through the fluid port 18.

The reduced diameter portion 31 of the trip valve element 28 provides means for exhausting the pneumatic fluid from the cylinder 16 through the passageway 32 whenever the trip pin portion 31 has been actuated or depressed relative to the housing 2% to the position shown in FIG. 3. In this position, the large diameter portion 39 of the trip valve element is disposed above the passageways 3% in the valve sleeve 25, and the cylinder 16 is connected to the atmosphere through the fluid port 13, the counterbore 22;, the bore 24, the passageways 38, the bore 2% and the passageway or opening 32.

The valve assembly 19 is actuated by a pivotally mounted trigger it? (FIG. 1) that is engageable with the trip pin portion 31 of the trip valve element 23. When the trigger 4t) is pivoted from its normal position illus trated in phantom in FIG. 1 to the depressed position i llustrated in sol-id in FIG. 1, the trip valve element 25*; s actuated from the position shown in FIG. 2 to the posh tion shown in FIG. 3. The compressed air in the bore 2? acts on the upper surface of the trip valve element 28 to return the trigger 4%) to its released position from its actuated position. v

To provide for the actuation of the trip valve 19 in response to movement ot the stapler 10 relative to a workpiece 14, the stapler It? may be provided with a trigger actuating mechanism, indicated generally at 4-1, that is illustrated in phantom in its released position and in solid line in its actuated position. The trigger actuating mechanism 41 comprises a rigid actuating bar 42 pivotally mounted at one end 42a to the stapler 1t and provided with a work engaging portion 43 at its other end which, in the released position, extends below the nosepiece 13 of the stapler to engage the workpiece 14. A connecting link 44 pivotally interconnects the actuat ing bar 42 adjacent its work engaging portion 433 and the trigger 40. I

In the normal condition of the valve assembly 19 (FIG. 2), air is admitted into the cylinder 16 through the passageways 35, 36, 37, 38, and 18 to maintain the iiirii-n control valve it closed. When the stapler It) is to be operated, the trip valve element 28 is moved upwardly from the position shown in FIG. 2 to the position shown in FIG. 3. During the initial upward movement of the element 28, the beveled portion 33 moves out of sealing engagement with the O-ring 34 and the passageways 37 are moved out of alignment with the passageways 33 t0 pr vent the admission of fluid into the cylinder 16. During continued movement of the trip valve element 25?, the lower end of the large diameter portion 30 moves above the passageways 33 in the valve sleeve 26 to connect the cylinder 16 to the atmosphere. The compressed air in the cylinder flows through the passageways lit"; and 33, around the reduced diameter portion 31 in the bore 299 and to the atmosphere through the passageway 32. When the compressed air is exhausted from the cylinder 16, the compressed air in the hollow handle moves the piston 15 of the main control valve 11 downwardly to connect the reservoir of compressed air in the hollow handle to the cylinder containing the drive piston.

Upon release of the valve element 28, fluid pressure in the valve chamber above the valve element 28 is effective to return the valve element 28 to its normal position. In this position, the passageway formed in the bore 29 between the passageway 38 and the aperture 32 is closed jointly by the large diameter portion 3t) of the valve element 28 moving over the opening of the passageway 38 and by the sealing of the beveled portion 33 against the O-ring 34. The passageway 37 in the valve element 2-8 aligns with the passageway 38 in the valve sleeve 26 and compressed air again enters the cylinder 16 to close the control valve 11.

The member 23 can be adjusted to change the position of the trip pin portion 31 relative to the housing 249 and the stapler 10. This is readily accomplished by threading the adjusting member 23 into or out of the counterbore 22 of the housing 29 to move the valve sleeve 26 and the trip valve element 28 relative to the housing 20. The extreme inner and outer positions of the valve assembly 19 are shown in FIGS. 2 and 3. In FIG. 2, the valve assembly 19 is shown in a released or normal condition, and the member 23 has been adjusted to its outer position. In FIG. 3, the valve assembly 19 is shown in an operated condition, and the member 23 has been manually adjusted to its extreme inner position.

To actuate the stapler ill by movement thereof toward a workpiece 14, with the actuating bar 42 in the position illustrated in phantom, the work engaging portion 43 thereof butts against the workpiece lid and is depressed relative to the stapler l0, depressing the trigger 41) to depress and thereby actuate the trip valve element 23, thereby actuating the trip valve 19 to operate the stapler it). Upon withdrawal of the stapler it) away from the workpiece 14, the actuating bar 42 is returned to its released position by the pneumatic force acting on the trip valve element 28, thereby preparing the stapler for a subsequent operation.

The position or" the stapler 10 relative to the workpiece 14 at which the stapler It) operates may be controlled by adjustment of the member 23. Movement of the member 23 into the counterbore 22 changes the position of the trip valve element 28 and thereby varies the position at which the trigger ill will move the trip valve element to operate the stapler. This change in operating position of the trigger it) results in a change in the position of the work engaging portion 43 of the actuating bar 42 relative to the workpiece 4 at which the trip valve element 28 is actuated.

The improved trip valve 19 is operable with a minimum force and requires a suflicient travel of the element 28 between the normal and operated positions to avoid accidental operation of the stapler ltl due to the recoil of the device. Moreover, the adjusting member 23 of the trip valve 19 provides for variation in the dimension of the stapler and linkages and, additionally, permits the selection of the operating point of the stapler 10 relative to the workpiece 14. as desired by the operator.

Although a particular embodiment of the present invention has been described, it is obvious that those skilled in the art may devise other embodiments and modifications which fall within the true spirit and scope of the principles of this invention.

What is claimed as new and is desired to be secured by Letters Patent of the United States is:

1. A trip valve for controlling a fastener driving apparatus of the type including pneumatically operated fastener driving means and having a control for operating said means actuated by the admission and exhaust of pneumatic fluid therefrom, said trip valve comprising a housing forming a valve chamber, a valve sleeve in said housing, said sleeve containing at least a first passageway adapted to communicate with said control for said fastener diving apparatus, and a trip valve element slidably received in said sleeve, said trip valve element being movable between a released and a depressed position and provided with a second passageway interconnecting said chamber and said first passageway when the trip valve element is in a released position, said housing being provided with a passageway communicating with said chamber and adapted to be connected to a source of fluid supply.

2. A trip valve as set forth in claim 1 above and including passageway means for connecting said first passageway to the atmosphere whenever said trip valve element is in a depressed position.

3. A trip valve for controlling a fastener driving apparatus of the type including pneumatically operated fastener driving means and having a control for operating said means actuated by the admission and exhaust of pneumatic fluid th refrom, said trip valve comprising a housing forming a valve chamber, a valve sleeve in said housing, a trip valve element slidably received in said sleeve, said trip valve element being movable between a released and a depressed position and provided with a central passageway extending longitudinally partially through said element and communicating with said chamber, said trip valve element additionally being provided with at least one radially extending passageway intermediate the length of said element and communicating with said central passageway, said sleeve containing at least one passageway aligned with the said radially extending passageway when said trip valve element is in its released position and adapted to communicate with said control for said fastener driving apparatus, said housing being provided with a passageway communicating with said chamber and adapted to be connected to a source of fluid supply.

4. A trip valve as set forth in claim 3 above and including a passageway for connecting said one passageway to the atmosphere whenever said trip valve element is in a depressed position.

5. A trip valve for controlling a faster driving apparatus of the type including pneumatically operated fastener driving means and having a control for operating said means actuated by the admission and exhaust of pneumatic fluid therefrom, s aid trip valve comprising a housing forming a valve chamber, an adjusting cylinder telescopically secured within said housing, a valve sleeve positioned in said valve chamber and mounted within said cylinder, first passageway means extending through said sleeve and adapted to communicate with said control for said fastener driving apparatus, a trip valve element slidably received in said sleeve, said trip valve element being movable between a released and a depressed position and provided with a second passageway interconnecting said chamber and said first passageway when said trip valve element is in said released position, said housing being provided with a passageway communicating with said chamber and adapted to be connected to a source of fluid supply, and means for telescopically adjusting said cylinder in said housing to position said sleeve and said trip valve element in unison relative to said housing.

6. A trip valve for controlling a fastener driving apparatus of the type including pneumatically operated fastener driving means and having a control for operating said means actuated by the admission and exhaust of pneumatic fluid therefrom, said trip valve comprising a housing forming a chamber having an aperture at one end thereof, a valve sleeve in said housing, said sleeve containing at least a first passageway adapted to communicate with said control for said fastener driving apparatus, a trip valve element having an enlarged diameter portion slidably received in said sleeve and a. trip portion of smaller diameter than said aperture and extending through said aperture, said trip valve element being movable between a released and a depressed position and provided with a second passageway interconnecting said chamber and said first passageway when said element is in said released position, said housing being provided with a third passageway communicating with said chamber and adapted to be connected to a fluid pressure source and fourth passageway means formed between said trip portion and said aperture and interconnecting said first passageway and the atmosphere when said trip valve element is in a depressed position.

7. A trip valve for controlling the admission and exhaust of pneumatic fluid from a device and comprising a housing forming a valve chamber, sleeve means in said chamber, first passageway means in said sleeve means adapted to be connected to said device, valve means slidably received in said sleeve means for movement be tween 21 first position and a second position, second passageway means in said valve means communicating with said chamber and aligned with said first passageway means when said valve means are in its first position, means communicating with said chamber and adapted to be connected to a source of fluid supply, means for moving said valve means to said second position from said first position to move said second passageway means out of align ment with said first passageway means, and means connecting said first passageway means to the atmosphere whenever said valve means is in said second position.

8. A trip valve as set forth in claim 7 above and including means for adiustably moving said sleeve means and said valve means in unison within said housing.

9. The improvement in a fastener driving apparatus responsive to relative movement thereof toward a workpiece, said apparatus being of the type including pneumatically operated fas ener driving means and having a control for operating said means actuated by the admission exhaust of the pneumatic iiuid therefrom, said improvement comprising a trip valve including a housing forming a valve chamber, a valve sleeve in said housing, said valve sleeve containing at least a first passageway adapted to communicate with said control for the fastener driving apparatus, a trip valve element slidably received in said sleeve, said trip valve element movable between a released and a depressed position and provided with a second passageway interconnecting said chamber and said first passageway when said valve element is in said released position, said housing being provided with a third passageway communicating with said chamber and adapted to be connected to a source of fluid supply, fourth passageway means for connecting said first passageway to the atmosphere whenever said trip valve element is in a depressed position; trigger means for depressing said trip valve element; and a trigger actuating mechanism responsive to relative movement of said apparatus toward a workpiece, said mechanism including a rigid actuating bar pivotally mounted at one end thereof to said fastener driving apparatus and provided with a work engaging portion, and means pivotally connecting said actuating 8 bar adjacent its work engaging portion and said triggx means.

10. A trip valve as set forth in claim 9 above and additionally including means for adjustably moving said valve sleeve and said trip valve element in unison witln'n said housing to adjust the position from said workpiece at which said element is moved relative to said sleeve.

11. In a fastener driving apparatus having a housing forming a cylinder in which a drive piston is slidably mounted, valve means carried on said housing for supplying a pressure fluid to said cylinder for actuating said drive piston, said valve means including a valve element and support means in which said valve element is movably mounted for movement between a normal position in which pressure fluid is not supplied to said cylinder and an actuated position in which pressure fluid is supplied to said cylinder, valve operating means carried on said housing and operable by engagement with a workpiece for moving said valve element from said normal position to said actuated position, said valve operating means including a valve actuator element mounted on said housing for a predetermined degree of movement, and means for adjusting the osition of said valve element and said support means on said housing relative to both said valve actuator element and said valve means that said valve element can be operated to said actuate position during different selected portions of said predetermined degree of movement of said valve actuator element.

References Cited in the file of this patent UNITED STATES PATENTS 

11. IN A FASTENER DRIVING APPARATUS HAVING A HOUSING FORMING A CYLINDER IN WHICH A DRIVE PISTON IS SLIDABLY MOUNTED, VALVE MEANS CARRIED ON SAID HOUSING FOR SUPPLYING A PRESSURE FLUID TO SAID CYLINDER FOR ACTUATING SAID DRIVE PISTON, SAID VALVE MEANS INCLUDING A VALVE ELEMENT AND SUPPORT MEANS IN WHICH SAID VALVE ELEMENT IS MOVABLY MOUNTED FOR MOVEMENT BETWEEN A NORMAL POSITION IN WHICH PRESSURE FLUID IS NOT SUPPLIED TO SAID CYLINDER AND AN ACTUATED POSITION IN WHICH PRESSURE FLUID IS SUPPLIED TO SAID CYLINDER, VALVE OPERATING MEANS CARRIED ON SAID HOUSING AND OPERABLE BY ENGAGEMENT WITH A WORKPIECE FOR MOVING SAID VALVE ELEMENT FROM SAID NORMAL POSITION TO SAID ACTUATED POSITION, SAID VALVE OPERATING MEANS INCLUDING A VALVE ACTUATOR ELEMENT MOUNTED ON SAID HOUSING FOR A PREDETERMINED DEGREE OF MOVEMENT, AND MEANS FOR ADJUSTING THE POSITION OF SAID VALVE ELEMENT AND SAID SUPPORT MEANS ON SAID HOUSING RELATIVE TO BOTH SAID VALVE ELEMENT CAN BE OPERATED TO SAID ACTUATED POSITION DURING DIFFERENT SELECTED PORTIONS OF SAID PREDETERMINED DEGREE OF MOVEMENT OF SAID VALVE ACTUATOR ELEMENT. 